Shrimp, also called jhinga in Hindi, is a valuable aquatic crop that has changed the lives of many farmers in India, especially those near the coastal belts. The most popular species being farmed is Litopenaeus vannamei, introduced to India around 2009-10. This species grows fast and fetches a good market price in both domestic and export markets. But diseases are a major challenge that can bring down the productivity and profitability of shrimp farming. If not managed timely, they can wipe out entire ponds in just a few days.
Let us understand how to keep shrimp healthy and avoid major disease outbreaks using preventive farming practices.
White Spot Disease (WSD)
WSD is one of the most destructive viral infections in shrimp, caused by the White Spot Syndrome Virus (WSSV). The disease spreads rapidly and can cause 100% mortality within a short time.
The signs of WSD are sudden reduction in feed intake, lethargy, reddish discoloration, and the presence of white spots (1-2 mm in size) on the shell and body of shrimp.
To prevent WSD, always use virus-free Specific Pathogen-Free (SPF) seed from certified hatcheries. Maintain biosecurity by disinfecting ponds before stocking, avoiding bird entry, and not using untreated water. Use effective probiotics and mineral supplements to boost shrimp immunity.
Early Mortality Syndrome (EMS)
EMS, also known as Acute Hepatopancreatic Necrosis Disease (AHPND), affects young shrimp within 20-30 days of stocking. It is caused by a toxin-producing bacteria Vibrio parahaemolyticus.
The symptoms include low or no feed intake, loose shells, pale or atrophied hepatopancreas (the organ behind the head), and rapid mortality.
To control EMS, proper pond preparation is crucial. Remove organic waste and plough the pond bottom well. Use chlorination or bleaching powder to disinfect. Apply good quality probiotics to outcompete harmful bacteria. Stock only SPF seed, and avoid overfeeding during the early stages.
EHP (Enterocytozoon hepatopenaei)
EHP is caused by a microsporidian parasite and leads to slow growth in shrimp. Affected shrimp appear normal but do not grow even after 30-40 days of culture. Feed conversion efficiency reduces, and size variation becomes common.
The best way to manage EHP is by preventing it. Use EHP-free seed, and ensure proper pond drying and disinfection before every crop. Avoid overfeeding and remove uneaten feed regularly. Using gut probiotics and enzyme supplements can help maintain a healthy gut in shrimp.
General Management for Disease Prevention
Farmers should follow these practical tips to ensure overall shrimp health:
-
Always test the quality of water and soil before every crop. The pH should be between 7.5-8.5, salinity should match hatchery values, and dissolved oxygen should be above 5 ppm.
-
Use clean water, and filter it before filling the pond. Avoid mixing water from unknown or polluted sources.
-
Do not stock beyond the carrying capacity. Overcrowding leads to stress and disease outbreaks. Maintain a stocking density of 40-60 PL/m² for vannamei depending on the pond size and aeration.
-
Apply probiotics regularly to control harmful bacteria in water and soil. Use organic acids and enzymes to improve digestion and gut health.
-
Observe shrimp behavior daily, especially during feeding. Sudden drop in feed intake is an early warning of disease.
-
Maintain proper record-keeping of feed usage, pond water parameters, and health status.
-
Dispose of dead shrimp safely and immediately to avoid contamination.
Role of Biosecurity and Farmer Awareness
The role of biosecurity is extremely important in shrimp culture. Simple practices like using footbaths, bird netting, disinfecting vehicles and equipment, and limiting farm entry can make a big difference in preventing diseases. Shrimp farmers must also regularly attend training programs, read farm bulletins, and stay updated about new disease trends.
Farmer producer groups (FPOs), cooperative societies, and government support systems must step forward to help small and marginal shrimp farmers with inputs, diagnosis, and disease control strategies.
Shrimp farming can be highly profitable if farmers focus on health management and preventive care. Most shrimp diseases are caused by poor pond hygiene, bad seed, or mismanagement. By following good aquaculture practices (GAP), using SPF seed, and maintaining strong biosecurity, farmers can reduce the chances of disease and increase their production and income.
Remember, in shrimp farming, prevention is always better and cheaper than cure. Healthy shrimp means happy ponds and prosperous farmers.
